Mobile devices divided into several parts that are used in various combinations are being developed. So-called multipart radio terminals, for example, may include a very small cellular core unit and a number of optimized peripheral units. The peripheral units of the multipart radio terminals are optimized for specific tasks and all the peripheral units are connected to a core unit by low power radio frequency (LPRF) connections, such as Bluetooth connections. One of the peripheral units may be optimized for making basic phone calls and another peripheral unit may be optimized for messaging and browsing or for imaging and music, for example.
When a new connection is to be established to a multipart radio terminal the indication of the incoming connection is made in one or in all of the peripheral units. Preferably, calls cannot be made or answered by a core unit because it has no user interface or a very minimal user interface. It is typical that the core unit does not indicate any incoming calls or SMS (Short Message Service) messages. The calls are answered or the SMS messages are received in one of the peripheral units of the multipart radio terminal. One peripheral unit at a time may represent a default device where all incoming connections are routed. It is also possible that all the peripheral units are indicating the incoming connections and the user may accept the call or read the SMS message from any one of the peripheral units. Also, the incoming call indication settings, such as ringing tones, are set in each peripheral unit as desired.
A problem with this kind of indication of incoming connections arises if for some reason the LPRF connection between the core unit and the peripheral unit in which the incoming connection is to be indicated, is not available. This is possible in a situation where the peripheral unit has moved too far away from the core unit, for example. If the LPRF connection between the core unit and the peripheral unit is not available, it is possible that the user of the multipart radio terminal will not be alarmed about any incoming connections. If on the other hand, both the core unit and the peripheral units are set to inform about the incoming connections, the user-friendliness of the multipart radio terminal becomes very poor. It is extremely disturbing and stressful for the user if all the devices of the multipart radio terminal are ringing always at the same time, for example. Also, for usability reasons, it is not sensible that such a device that cannot be used to accept any calls always informs about incoming calls, for example.